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RetroRob
06-23-2012, 6:29 PM
Making my own velocity stack for my single carb 650.Whats the ideal length for normal street riding.

Torch
06-23-2012, 10:09 PM
if you have a stock frame the area between a center mounted carb and the downtube is only about 2.5",
it's just easier to buy a short velocity stack.

RetroRob
06-24-2012, 8:07 AM
Thanks

TD
06-24-2012, 9:08 AM
Is there much performance gain from running a velocity stack vs. the stock OIF filter?

td

RetroRob
06-24-2012, 11:48 AM
probably very little, just looks a lot better in my opinion

worn
06-24-2012, 12:19 PM
I've run them on a '67 Bonneville, felt no difference between the stock filter housings with K&N filters and velocity stacks.

TD
06-24-2012, 2:20 PM
Thanks guys. Worn I was talking more about an OIF setup which I heard restricts the air flow to about 3/4.

I can always just run the carb open and see if I can feel anything.

td

RetroRob
06-24-2012, 5:45 PM
If the bike is running good now you might have to rejet due to the increased air flow.

dazegoneby
06-27-2012, 11:00 PM
I run the short amal stacks due to oif .the length i usualy see is 4 to 4,1/2 in long stacks where clearence is not a issue.the amals have no screens these short stacks are either black or silver plastic,roughly inch long.i do feel difference than ,without stack ,or with air filter.i jetted carbs to stacks, also ,,I,m running drag pipes with short baffels

RetroRob
06-29-2012, 9:52 AM
can someone measure from the back of an amal 930 to the down tube on a single carb 650 ? I'm making a velocity stack and dont have my motor back from the shop yet.

SMITHSIDEBAR
06-29-2012, 10:25 AM
Since the stack is an open element, I wouldn't think length would matter as much as turbulence and keeping an obstructions out of the path of the air into the carb. Can you modify the manifold to be able to run the length you like?

RetroRob
06-29-2012, 8:14 PM
Since the stack is an open element, I wouldn't think length would matter as much as turbulence and keeping an obstructions out of the path of the air into the carb. Can you modify the manifold to be able to run the length you like?

Might be able to mill things down a bit, it's critical to keep the mounting flanges flat and parallel so for me cutting down the stack with a hack saw is a lot easier.

starwolf
06-29-2012, 10:07 PM
Might be able to mill things down a bit, it's critical to keep the mounting flanges flat and parallel so for me cutting down the stack with a hack saw is a lot easier.

Be careful how ya do it, if you cut too much off of the threaded side you wont be able to screw them on, because of how they are flanged you wont be able to rethread them either. Cut from the outer side